SiC (silicon carbide) is superior in dielectric breakdown resistance and thermal conductivity etc. to Si (silicon). Therefore, SiC is watched with interest as a semiconductor suitable to a use for an inverter of a hybrid car or the like, for example. More specifically, a MISFET (Metal Insulator Semiconductor Field Effect Transistor) employing SiC is expected as a high withstand voltage device suitable to an inverter of a hybrid car or the like.
A MOSFET (Metal Oxide Semiconductor Field Effect Transistor) as an example of a MISFET employing SiC has an SiC-MOS structure obtained by stacking a gate electrode on an SiC substrate through a gate insulating film made of SiO2 (silicon oxide). A well region is formed on a surface layer portion of the SiC substrate. A source region and a drain region are formed on a surface layer portion of the well region at an interval from each other. The gate insulating film is formed on a region between the source region and the drain region.